Therapeutic-anesthetic preparations



Patented Sept. 18, 1945 THERAPEUTIC-ANESTHETIC PREPARATIONS David Curtis, New York, N. Y.

No Drawing.

Claims.

The present invention relates to therapeutic antiseptic preparations and to fabric dressings impregnated therewith and more particularly to preparations and impregnated dressings having bacteriostatic, germicidal and anesthetic properties, suitable forexternal application.

It is an object of the present invention to provide preparations of the character described containing, in solution, substances having bacteriostatic, germicidal and anesthetic properties.

It is another object of the present invention to provide solutions of the character described which are substantially non-volatile under ordinary conditions and which may, therefore, be employed to successfully impregnate fabric dressings which will remain in a moist condition and in which the ingredients will be retained in solution for a prolonged period of time.

It is also an object of the present invention to provide gauze bandages and other fabric dressings impregnated with solutions of substantial stability containing therapeutic and anesthetic substances.

It is a further object of the present invention to obtain solutions of the character described and fabric dressings impregnated therewith containing boric acid to render the active ingredients more efficacious by reason of the penetrability of the boric acid present therein.

It is a still further object of the present inven tlon to provide easy and efficient methods for forming the preparations of the present invention.

More specifically stated, the present invention has for its object to bring together in substantially stable solution, the highly desirable and sparingly soluble anesthetic substances such as benzocaine or other alkyl-para-amino benzoates, and the equally desirable antiseptic, bacteriostatic substances from the group of sulfa-products, such as sulfanilamide and its derivatives and related substances, together with other antiseptic, bacteriostatic substances to amplify the therapeutic value of the finished product, such solutions being formed in glycerine or similar "non-volatile substances, which thereby become f bandages impregnated therewith which when applied to the wounds, will relieve the pain and irritation and at the same time prevent and control any infections, without, however, interfering with the normal bodily healing processes.

In my preparations I, therefore, utilizaas an anesthetic and antiseptic therapeutic substance,

Application December 10, 1941, Serial No. 422,328

a condensed product formedby the union of an alkyl-para-amino-benzoate such as benzocaine, which is a highly efiicacious anesthetic substance, and of a substance from the group of sulfa-products such as sulfanilamide, which is a highly effective and efficient antiseptic and bacteriostatic substance.

sulfanilamide (para-amino benzene sulfonamide, having the formula H2N.C6H4.SO2.NH2) is effective against hemolytic streptococcic and meningococcic infections and is of value in certain uro-genital infections. It renders human virulent strains of hemolytic streptococcic more susceptible to the bactericidal action of human blood (C. H. Lyons et a1.Am. Surg., V. 108, pp. 813-21--1938).

It is also known that sulfanilamide, when added to ascitic broth, produces bacteriostasis. When the inoeulum is small, the organism fails to survive. The effect 'of sulfanilamide added directly to human blood or plasma produces the same effect even when heated for two hours at 56 C. This indicates that the bactericidal power is due to the sulfanilamide and not to other factors that may be present in the blood (Ch. S. Keefer et al.,

Amer. Jour. of Syphilis, Gonorrhea and Venereal Sulfathiazole (2-sulfanilamido-thiazole) prov longs the lives of mice which are infected with a virulent strain of Staphylococcus aureus and also prevents the development and permits the healing of kidney abscesses and abscesses in other organs (Barrow et al., Proc. Soc. Expt. Biol. Med, V. 42, pp. 792-7 (1939)).

There is also ample clinical corroborative information to the effect that sulfanilamide, placed into a wound soon after formation, produces beneficial results, prevents infection and enhances recovery.

Generally stated, the preparation of the present invention may be prepared by adding an alkyl ester of amino benzoic acid together with a sulfa-product to glycerine or to a solution of boric acid in glycerine, and heating the mixture on a hot plate until solution takes place; the alkylamino-benzoate and the sulfa-substance being present preferably in equimolecular proportions. Thereafter another antiseptic bacteristatic substance as well as other desired ingredients may be added to the solution.

The anesthetic substances that may be used include the alkyl amino benzoate group, and the alkyl-hydroxy-amino-benzoate group, such as benzocaine, propyl-p-amino benzoate, butyl-pamino benzoate (butesin), and the like, and orthoform, also known as methyl-para-oxymetamino benzoate and the like.

The sulfa-products that may be used incl de sulfanilamide and its various derivatives and related products. The derivatives of sulfanilamide include para-benzyl-amino-benzene sulfonamide, acetyl-sulfanilamide, orthanilamide and metanilamide, disuli'anilamide, para-hydroxylaminobenzene-sulfonamide, para amino-benzenesulfonhydroxyethylamide (soluble in less than 10 parts of water), para-aminobenzene-sulfonyl-acetamide and sodium-sulfanilamide, and others. In the related group the following may be included, sulfapyridine, sulfathiazole and sulfadiazine and others.

Of additional antiseptics that may be added, which are especially suited for gauze impregnation, the following may be mentioned: 8-hydroxyquinoline sulphate (C9H10N)=H2SO4, thymol, chlorothymol, eucalyptus, hydronaphthol, and the like.

Although the alkyl-esters of amino-benzoic acid are sparingly soluble substances, I have found that in the presence of sulfanilamide or similar substance, they can be brought into solution in a medium such as glycerine, in appreciable quantities, by forming an addition product, and that such solutions, except when in highly concentrated form, remain sufliciently long in solution for clinical use;

I have found further that by the addition of an alcohol, such as ethyl, isopropyl, and particularly, benzyl, or glycol or diethylene or propylene glycol or the ethers of such glycols and, in particular, the monoethyl ether of diethylene glycol, the glycerine solution of the addition product of benzocaine and sulfanilamide will be rendered more lasting, and whenadded in suflicient quantitles will render such solution substantially stable.

The addition product of benzocaine and sulfanilamide will hereafter be referred to as Sulfonycaine."

The solubility of Sulfonycaine in hot glycerine is extensive, and hot solutions may be prepared containing as high as 40 gms. of the addition product to 60 cc. of glycerine. When such solution shows precipitation on cooling, it will leave a paste which can be used as a salve or ointment, and generally, solutions of Sulfonycaine in glycerine in which precipitation forms, may be re-formed into solution by re-heating.

When prepared in lesser concentration, such as about a 10% solution of the Sulfonycaine, such solution may remain fiuid for at least several hours after formation, sufflciently long to be used for clinical purposes. In all instances, where precipitation takes place, the addition product may be redissolved through the simple expedient of heating the solution on a water bath or by placing the container in hot water and kept there for some time.

The solutions of Sulfonycaine in glycerine, in all concentrations, may be rendered more lasting by the addition of any of the alcohols or glycol derivatives named above; with the length of time in which the solution will stand up increasing as the proportion of the additional solvent is increased.

The solution of Sulfonycaine in glycerine may be formed by adding substantiall equimolecular proportions of benzocaine and sulfanilamide to glycerine and heating the mixture on a hot plate until solution takes place. When a more stable or lasting solution is desired, the additional solassume vent may be mixed with the glycerine before the addition of the active ingredients, with the benefit of more rapid dissolution of the same. By way of example, the following preparations may be given.

Example 1.-4.125 gms. of benzocaine and 4.3 gms. of sulfanilamide are added to 70 cc. of glycerine and the mixture heated on a hot plate until solution takes place. Such solution, when cooled, will stand up for several hours, or sufliciently long for clinical use. benzyl alcohol or mono-ethyl ether of dlethylene glycol or a mixture of both and glycerine are added to make a final volume of 100 cc., the solution will be rendered relatively more stable. (In the sense of remaining longer in solution.)

I have further found that when the addition product is formed and dissolved in glycerine containing boric acid a solution of greater durability is formed than when glycerine alone is used as the solvent.

Thus, when equimolecular proportions of benzocaine and sulfanilamide sufficient to produce gms. of the condensed Sulfonycaine are dissolved in '75 cc. of glycerine (by heating on a hot plate) and the Whole then made up to 100 cc. with glycerine, the solution stands up only for several hours.

However, when 5 gms. of boric acid are dissolved in the glycerine before adding the ingredients of the Sulfonycaine as above, the resulting solution will remain liquid for about hours, indicating greater solution stability.

I have found that the greater the concentration of boric acid dissolved in the glycerine, the longer the Sulfonycaine will remain insolution without precipitatin and the more rapidly will it go into solution. A convenient and preferred form of boric acid compound dissolved in glycerine, which is available in the market in ready for use is boro-glycerite; which contains the equivalent of about 31% of boric acid in glycerine.

I believe that the greater and more rapid dissolution of the Sulfonycaine in a boric acid-glycerine solvent, may be accounted for by the formation of a compound of the Sulfonycaine with the boric acid, and, in boro-glycerite, also to the ester nature of the latter compound.

For practical purposes, to obtain effective therapeutic value as well as adequate stability of solution with a minimum of boric acid, it is desirable to use from about 4 to about 6 molar equivalents of boric acid to one molar equivalent of Sulfonycaine, with the solid ingredients constituting between 30 to 35% by weight/volume of the final solution, which besides glycerine should contain, for greater solution stability, between 10 and 25%, by volume, of the supporting additive solvent, from the group'mentioned above. The following preparations may servev as examples of preferred formulas.

Example 2 Sulfanilamide "I "gms-- 8.6 Benzocaine gms 8.25

which is s, 4 molar equivalent to the combined sulianilamide and benzocaine.

. Benzyl alcohol cc 10 to 25 in glycerine, to make up cc. of solution.

When 20 cc. of v Ewnple 3 Butesin m 9.66 Sulfanilamide ..-gms 8.6

To form 18.26 gins. of the butesin-sulfanilamide addition product.

Boric acid gms 12.4

4 molar equivalent.

Benzyl alcohol cc l5 in glycerine, to make up 100 cc. of solution.

Example 4 Orthoform gms 8.85 Sulfanilamide gms 8.6

to form 16.95 gms. of the orthoform-sulfanilamide addition product.

Boro-glycerite gms 40 containing, or adjusted to contain 12.4 gms. o1 boric acid.

equimolar amounts to form a sulfapyridlne-benzocaine addition product.

Boric acid "gins..- 6.2

5 molar equivalent.

Benzyl alcohol cc to Mono-ethyl ether of diethylene glycol cc 15 in glycerine, to make a final volume of 100 cc.

Example 8 Sulfonycaine gms Boro-glycerite gms 34.5

containing, or adjusted to contain 10.7 gms. boric acid.

Mono-ethyl ether of diethylene glycol.... cc

in glycerine, to make final volume of 100 cc.

The bactericidal and bacteristatic properties of any of the solutions and preparations made in accordance with the foregoing discussion may be amplified by the addition of another agent suitable for the purpose, in accordance with the recognized principle that two different bactericidal agents potentiate the action of each other. A suitable and desirable substance for that purpose, especially when intended for gauze impregnation, is oxyquinoline sulphate, which may be used in a concentration of 0.1% to 2.0%. The

other additional antiseptics named above may, oi course, also be used, in the accepted and suitable concentrations. The presence of the additive solvents also contributes to enhance the solubility of the additive antiseptics in the solutions.

While the preparations described may be directly used, as surface anesthetic antiseptics, in liquid, salve or ointment form, they are particularly adaptable for use, in solution form, for impregnating gauze and other fabric dressings. For this purpose the glycerine solutions, adjusted for greater solution stability by the addition of any of the additive solvents in the required volume, may be diluted with a volatile solvent, such as ethyl alcohol, acetone or the like, for greater manageability and ease of production. Such volatile vehicle is subsequently driven ofi by the application of currents of warm sterilized air, leaving a moist deposit of the active ingredients, in solution, thoroughly impregnated into the gauze.

It will be obvious that in order to obtain any given concentration of the active ingredients upon the gauze, the concentration of the initial solution and the degree of its dilution with the volatile vehicle must be previously calculated and regulated accordingly.

For commercial and practical purposes, the impregnated dressings may be placed individually or in quantities in suitable sterile, water and air impervious containers, which may be made of plastics or rubber or other materials useful for the purpose. Metallic containers may also be used if previously lined with melted par aflln sterilized by heat. The dressings may thus be kept permanently slightly moist.

This completes the description of the products of the present invention and of the methods for preparing the same. It is to be understood that the examples given herein are by way of illustration onhr, and are not intended to limit the scope of the invention to the substances and their products therein given. Thus, it may be stated that preparations and gauze bandages impregnated therewith may be prepared, in which the active anesthetic and antiseptic substances may be present in concentrations as low as one-half of one per cent, which solutions and dressings may have definite therapeutic uses, as in eye work or in the treatment of infants and the like. I, therefore, desire the protection of the patent laws for all variations and modifications of the preparations and products of the present invention that are within the spirit of the invention and within the scope of the claims hereto appended.

What I claim is:

1. As a new composition of matter, an addition product of alkyl ester of amino-benzoic acid and a sulfonamide compound from the group consisting of sulfanilamide, sulfapyridine, sulfathiazole and sulfadiazine, dissolved in glycerine.

2. As a new composition of matter, an addition product of alkyl ester of amino-benzoic acid and a sulfonamide compound from the group consisting of sulfanilamide, sulfapyridine, sulfathiazole and sulfadiazine, dissolved in a solvent comprising a solution of boric acid in glycerine.

3. As a new composition of matter, an addition product of alkyl ester of amino-benzoic acid and a sulfonamide compound from the group consisting of sulfanilamide, sulfapyridine, sulfathiazole and sulfadiazine dissolved in a mixture of glycerine and a liquid from the group of ethyl alcohol, isopropyl alcohol, benzyl alcohol, glycol, di-

ethylene glycol, propylene glycol and the alkyl ethers of diethylene and propylene glycol.

1 4. As a new composition of matter, an addition product of alkyl ester of amino-benzoic acid and a sulionamide compound from the group consisting of sulianilamide, suliapyridine, suliathiazole and suliadiazine, dissolved in a solvent comprisingv a mixture of a solution of boric acid in glycerine and a liquid from the group of ethyl alcohol,

isopropyl alcohol, benzyl alcohol, glycol, diethylene glycol, propylene glycol and the alkyl ethers of diethyene and propylene glycol.

assasea 9. As a composition of matter, a solution comprising an addition product or substantially equimolecular proportions of an alkyl ester of amino-.

benzoic acid and a suli'onamide compound from the group consisting oi sulianilamirle, suliapyridine, suliathiazole and suliadiazine. and boric acid, in the proportion about four to about six 5. As a new composition of matter, an addition product of benzocaine base and a sulionamide compound from the group consisting of sulfanilamide, suliapyridine, sulfathiazole and suliadiazine, dissolved in glycerine.

6. As a new composition of matter, an addition product or benzocaine base and a sulfonamide compound from the group consisting of sulfanilamide, suliapyridine, sulfathiazole and sulfadiazine, dissolved in a solution of boric acid in glvcerine.

molar equivalents to one molar equivalent or the combined ester and sulfa substance, in glycerine,

in a concentration oi! between about gms. to

about 35 gms. oi the solid ingredients to 100 cc. of the final solution.

10. As a composition of matter, 'a solution comprising an addition product of substantially equimolecular proportions of an alkyl ester of aminobenzoic acid and a sulionamide compound from the group consisting of sulfanilamide, sultapyri- 7. As a new composition of matter, an addition product of butesin and a sulfonamide compound from'the group consisting of sulfanilamide, sulfapyridine, sulfathiazole and sultadiazine, dissolved in a solution of boric acid in glycerine.

8. As a new composition or matter, a solution comprising an addition product of orthoform and a sulfonamide compound Irom the group consisting of sulfanilamide, suliapyridine, sulfathlazole' and sulfadiazine dissolved in a solution of boric acid in glycerine.

dine, suliathlazole and sulfadiazine, and boric acid, in the proportion of about four to about six molar equivalents to one molar equivalent of the DAVID CURTIS. 

